1. Field of the Invention
This invention pertains in general to the field of propelling apparatus for generation of a thrust or for fluid flow, and in particular to the field of blade apparatus for powering a shaft, propelling a vehicle or for pumping a fluid, gas, liquid or any other mixture, or any other medium.
2. Description of the Related Art
Blades are commonly used in various devices, such as propellers, turbines, pumps, blowers, fans and other like apparatus. Whether used as a propeller or an impeller, an aircraft propeller, boat propeller or a fan, the blades themselves are essentially the same. Typically, the blades are twisted, angled and symmetrically arranged around the circumference of a hub or shaft.
The basic blade design has not changed for many years. What differs is the blade orientation, the medium being moved by the blades and the direction of movement. The blades may be structured to either propel a medium, such as a liquid, gas or slurry past the blades or to cause a medium to impinge upon the blades to cause rotation of the blades about a shaft. For example, a boat propeller generally consists of two or more blades twisted and raked backwards to propel water away from the boat, thereby propelling the boat forward. Furthermore, the propeller's performance is a function of the overall diameter, the amount of rake and the pitch of the blades. Blades having low pitch angles are generally more power producing than blades having high pitch angles, whereas blades having high pitch angles generally produce greater speed.
While there exist a number of inventions which are said to increase the performance of propellers and impellers, such inventions utilize the basic blade design discussed above. Such inventions merely include changes to the rake and pitch angles or add vanes to the blades.
Although somewhat useful for their intended purpose, these prior art blades include certain inherent limitations and, therefore, have not proven to be entirely satisfactory. Specifically, the rake and pitch which may be achieved using the prior art blades is limited because the transverse flow components of the prior art blades are diminished at the inner and outer ends of the blades, thereby wasting energy and losing efficiency. This is best illustrated by reference to FIG. 14A which shows that there is virtually no useful flow produced by the prior art blades at the inner proximate end and outer distal end of the blades. Furthermore, due to such inefficient waste of energy, the prior art blades are often unstable and must be constructed of rigid materials to maintain their stability. For instance, ceiling fan blades are often difficult to balance and frequently become unbalanced over time due to their inefficient operation. Moreover, being restricted to rigid materials increases the cost of devices utilizing these prior art blades and limits the design alternatives, both functional and aesthetic, which can be achieved if other more flexible materials were used.
Some devices have been developed which differ from the standard prior art blade configurations discussed. Most merely change the blade orientation with respect to the shaft so that the longitudinal axis of the blades are parallel to the shaft. Typically, these devices are specifically designed for use with wind turbines or mixers or agitators in a vertical orientation. However, there is no suggestion in these prior art devices to orient the blades horizontally or in perpendicular relation to the shaft and there is no indication or suggestion that such vertically oriented blades will have any effect upon the transverse energy or stability of the blades.
Another device, shown in U.S. Pat. No. 5,411,330, discloses a mixing accessory which comprises a pair of moebius FIG. 8 shaped blades longitudinally disposed along parallel shafts. However, this device, like the other prior art devices discussed above, is specifically designed for mixing or agitating and is vertically oriented along the shaft. The lack of disclosure, suggestion or teaching in the prior art problem addressed by applicant supports the conclusion that part of applicant's invention is the discovery of the problem, that is, the need for a propeller/impeller blade structured so that the transverse energy is not diminished at the inner and outer ends of the blade, thereby providing more efficient operation, improved rake and pitch and greater stability.
Accordingly, there is still a need in the art for a propeller/impeller blade structured so that the transverse energy is not diminished at the inner and outer ends of the blade, thereby providing more efficient operation, improved rake and pitch and greater stability. Any such device should allow for the use of a wide range of materials to accommodate different applications and decrease the cost of the blades. The present invention is particularly suited to overcome those problems which remain in the art in a manner not previously known.